1. Field of Invention
The invention relates to an upper thread cassette and an upper thread changing device. More particularly, it relates to an upper thread cassette and an upper thread changing device that facilitate the performance of upper thread changing operations, such as when a color of an upper thread is changed during sewing operations.
2. Description of Related Art
Before starting sewing operations with a conventional sewing machine, some preparation is required. For example, a thread spool having a thread of a desirable color wound therearound is set to the sewing machine. An upper thread is pulled out of the thread spool and threaded on some mechanisms of the sewing machine, such as a thread guide, a thread tension guide, and a thread take-up. The upper thread is then passed through a needle eye. Especially when embroidering operations are performed for an embroidery pattern that requires a plurality of threads of different colors, an operator has to repeatedly perform the troublesome operations of setting thread spools on the sewing machine and threading upper threads on the above-described mechanisms of the sewing machine, as well as threading a needle, every time the embroidering operations with one color of the upper thread is finished and the color of the upper thread is changed to another.
In recent years, thread connecting devices, such as those described in U.S. Pat. No. 4,579,615 and Japanese Laid-Open Patent Publication No. 9-302571, that connect an end of a thread wound around one thread spool selected from a plurality of thread spools and an end of a thread threaded onto a sewing machine, are put into practical use. In the thread connecting device disclosed in U.S. Pat. No. 4,579,615, a thread connecting means cuts an upper thread, and holds an end of the upper thread belonging to or threaded onto a sewing machine and an end of an upper thread of a desirable color belonging to or wound around a thread spool, at a predetermined position. The thread connecting means connects the thread ends, through the medium of a connecting thread, by melting.
In a thread connecting device disclosed in Japanese Laid-Open Patent Publication No. 9-302571, vacuuming with a tube is started so as to move a thread clamp and a wiper toward a needle. After an end of an upper thread is clamped between an inner wall of the thread clamp and a vacuum ball, a hook and the thread clamp are moved by a cylinder toward an index. The vacuuming is stopped to return the thread clamp and the wiper to their original positions.
The clamped thread end is moved toward gears and the upper thread is drawn. Thereafter, the hook capturing the thread retracts. The distance between a pair of the gears is closed by the cylinder. An electric current is passed through a heating wire of a thread cutter and the upper thread is cut. Then, a knotter is moved by the cylinder to a thread knotting position. After the cylinder closes a tension disc, the thread knotting operations are performed by the cylinder.
In the conventional thread connecting device that employs thread spools, an upper thread is often pulled out of a thread spool to be longer than it needs to be, due to a reaction force of the thread wound around the thread spool (the force resulting as the thread tries to separate from the thread spool), resulting in slack in the upper thread in a path of the upper thread leading from the thread spool to a thread guide. Such slack causes the upper thread to get twisted, entangled, or overlapped, which leads to non-uniform upper thread tension. Consequently, the upper thread and an under thread are not properly tensioned, resulting in poor-looking stitches. In worse cases, the thread or a needle is broken.
As disclosed in Japanese Patent No.2650261, such an upper thread cassette containing an upper thread that applies uniform tension to the upper thread to be drawn and prevents the upper thread from being entangled is proposed and put into practical use. The upper thread cassette disclosed in Japanese Patent No. 2650261 includes a cassette body, a thread accommodating hole, an upper thread wound around an upper thread bobbin which is to be accommodated in the thread accommodating hole, an xe2x80x9cLxe2x80x9d-shaped plate spring, a pin, and a plurality of notches. While tension is applied to the upper thread by holding the upper thread between the plate spring and the pin, the upper thread is pulled through a thread pull-out hole. The tension applied to the upper thread is adjustable by engaging a protrusion of the plate spring with a different one of the notches.
Problems with the thread connecting devices disclosed in U.S. Pat. No. 4,579,615 and Japanese Laid-Open Patent Publication No. 9-302571, are they are expensive and they consist of large-sized devices having complicated structures.
In the conventional upper thread cassette disclosed in Japanese Patent No. 2650261, when a color of an upper thread is changed to a different color during sewing operations, the upper thread is cut and the upper thread cassette has to be removed from the sewing machine. Then, another upper thread cassette containing an upper thread of desirable color is set to the sewing machine, followed by the operations of threading the upper thread on a thread guide, a thread tension guide, and a thread take-up, and threading a needle. Thus, changes of upper thread colors require the troublesome operations.
In addition, when the upper thread cassette is not mounted, the upper thread needs to protrude, after cutting, from the upper thread cassette by an appropriate length, as a preparation for the next use (for the cassette remounting), so that a pressing force exerted between the plate spring and the pin needs to be set to high, to prevent the upper thread in the cassette from being excessively pulled out. When the upper thread cassette is mounted, the upper thread necessary for the sewing operations with the sewing machine has to be pulled from the upper thread cassette, so that the pressing force exerted between the plate spring and the pin needs to be set to low.
The invention provides an upper thread cassette and an upper thread changing device that facilitate upper thread changing operations to be performed, such as when a color of an upper thread is changed during sewing operations, as well as the upper thread changing device having a simplified structure so as to achieve a reduction in the size of the device.
According to one aspect of the invention, there is provided an upper thread cassette that contains an upper thread for use in sewing. The upper thread cassette may include a cassette member including a cassette body and a cassette cover that opens or closes the cassette body, a thread wound member mounting part that mounts thereon a thread wound member winding the upper thread therearound and is provided inside the cassette member, and a cutting mechanism that cuts the upper thread supplied from the thread wound member mounted on the thread wound member mounting part.
In the upper thread cassette of the invention, the thread wound member winding the upper thread therearound may be mounted on the thread wound member mounting part provided inside the cassette member. From the upper thread cassette, an end of the upper thread may be pulled out. Then, the cassette cover may be closed. The upper thread supplied from the thread wound member mounted on the thread wound member mounting part may be cut by the cutting mechanism. With the above-described structures, a pair of scissors or another cutter does not have to be prepared to cut the upper thread. Therefore, thread cutting operations may be improved.
The upper thread cassette may further include a thread end holding member that holds an end of the upper thread cut by the cutting mechanism. Because the cut upper thread may be held by the thread end holding member, an end of the upper thread does not have to be pulled out of the upper thread cassette every time the upper thread cassette is mounted. Consequently, the operation of changing a color of the upper thread during sewing operations is facilitated.
In the upper thread cassette, the cutting mechanism may cut the upper thread such that a cut end of the upper thread protrudes from the thread end holding member by a predetermined length. This structure may enable upper thread changing operations for changing a color of the upper thread to be automatically conducted by, for example, an upper thread changing device. Further, the upper thread may be prevented from unintentionally being released from the thread end holding member, being tangled, or being pulled into the upper thread cassette.
The cassette member may have an outlet that leads the end of the upper thread supplied from the thread wound member mounted on the thread wound member mounting part outside the cassette member. The thread end holding member and the cutting mechanism may be provided near the outlet, so that the upper thread may be cut by the cutting mechanism with an end thereof protruding outwardly from the cassette member, while preventing slack in the upper thread or the entanglement thereof.
Because the upper thread cassette may further include a tension applying mechanism that applies tension to upper thread supplied from the thread wound member mounted on the thread wound member mounting part, the tension may be applied to the upper thread supplied from the thread wound member by the tension applying mechanism.
As the upper thread cassette may further include a tension release operation part that releases the tension applied by the tension applying mechanism by externally operating the tension applying mechanism, the tension applied to the upper thread may be released by the tension release operation part. With this structure, the upper thread may readily be let out of the upper thread cassette.
The thread end holding member may serve as the tension applying mechanism. In other words, the end of the upper thread may be held by applying tension to the upper thread supplied from the thread wound member.
The thread wound member to be mounted on the thread wound member mounting part may include an upper thread bobbin having a narrow width provided in a direction of an axis thereof, relative to a diameter of the upper thread bobbin. The thread wound member mounting part may rotatably mount the upper thread bobbin thereon. With such a structure, the width of the upper thread cassette and, consequently, the size of the upper thread cassette may be reduced. The upper thread cassette may further include a brake mechanism that applies a brake to the upper thread bobbin mounted on the thread wound member mounting part. By applying the brake to the upper thread bobbin by the brake mechanism, rotation of the bobbin may be prevented.
Because the upper thread cassette may further include a brake releasing member that releases the brake applied by the brake mechanism by operating the brake mechanism outside the cassette member, the brake applied by the brake mechanism may be released with the brake releasing member by operating the brake mechanism outside the cassette member.
The thread wound member to be mounted on the thread wound member mounting part may include a thread spool. An existing thread spool may be applied as the thread wound member. The thread spool winding the upper thread therearound may be mounted on the thread wound member mounting part.
The upper thread cassette may further include a supporting shaft that pivotally supports the thread spool and is provided inside the cassette member, a shaft supporting member that fixedly supports the supporting shaft at an end thereof and is provided inside the cassette member, and a connecting mechanism that connects the shaft supporting member and the supporting shaft to the cassette member so as to allow the shaft supporting member and the supporting shaft to pivot in a range between a thread spool accommodating position where the thread spool is accommodated inside the cassette member, and a thread spool changing position where the supporting shaft is pivoted, as the cassette cover is opened, from the thread spool accommodating position to a position in which the supporting shaft is kept at an angle so as to enable the thread spool to be exchanged.
With the cassette cover open, the supporting shaft and the shaft supporting member may pivotally be moved with the connecting mechanism, to the thread spool changing position. In the thread spool changing position, the thread spool may be supported by the supporting shaft. Thereafter, the thread spool supported by the supporting shaft may pivotally be moved with the connecting mechanism to the thread spool accommodating position, together with the supporting shaft and the shaft supporting member. Then, the cassette cover may be closed. Thus, the upper thread cassette may be readied for use in sewing.
The upper thread cassette may further include a thread spool presser that is removably provided so as to press the thread spool pivotally supported by the supporting shaft. The thread spool presser may have a plurality of guide grooves that guide the upper thread and are formed on an outer edge thereof. After the thread spool is pivotally supported by the supporting shaft in the thread spool changing position, the thread spool presser may be mounted on the supporting shaft to press the thread spool. The upper thread supplied from the thread spool may be guided by the guide grooves of the thread spool presser, so that occurrences of slack in the upper thread or a twisted, entangled, or overlapped upper thread are prevented.
The thread spool presser may include a fixed part that is fixed on the supporting shaft and a movable part that is supported so as to move relative to the fixed part. The plurality of the guide grooves may be formed on an edge of the movable part. As the upper thread is supplied from the thread spool, the movable part may move while guiding the upper thread with one of the plurality of the guide grooves. Therefore, the occurrences of slack in the upper thread or a twisted, entangled, or overlapped upper thread may be reliably prevented.
The cassette member may be partially or totally formed of transparent material that enables the upper thread wound around the thread wound member set in the upper thread cassette to be visually identified. With this structure, a color and a remaining amount of the upper thread wound around the thread wound member may be visually identified outside the cassette member.
The cassette member and the upper thread bobbin may be partially or totally formed of transparent material that enables the upper thread wound around the upper thread bobbin set in the upper thread cassette to be visually identified. With this structure, a color and a remaining amount of the upper thread wound around the upper thread bobbin may be visually identified outside the cassette member.
The upper thread cassette may be mounted to an upper thread changing device that selectively supplies upper threads of a plurality of colors for embroidering. Therefore, embroidering may be performed by selectively supplying the upper thread of a desirable color from one of the upper thread cassettes for a plurality of colors mounted on the upper thread changing device.
The upper thread cassette may be mounted to a position on an arm of a sewing machine. Therefore, sewing operations may be performed by mounting the upper thread cassette, containing the upper thread of a desirable color, at an appropriate position on the arm of the sewing machine.
According to another aspect of the invention, there is provided an upper thread changing device that selectively supplies to a sewing machine upper threads of a plurality of colors for embroidering. The upper thread changing device may include a plurality of upper thread cassettes, each of which contains an upper thread of a different color, cassette mounting sections that detachably mount the plurality of the upper thread cassettes thereon, and a changing mechanism that changes positions of the cassette mounting sections so as to place any one of the plurality of the upper thread cassettes mounted on the cassette mounting sections to an upper thread supply position to supply the upper thread to the sewing machine.
In the upper thread changing device of the invention, the plurality of the upper thread cassettes may be mounted on the cassette mounting sections. The positions of the cassette mounting sections may be changed by the changing mechanism so as to place any one of the plurality of the upper thread cassettes mounted on the cassette mounting sections, to an upper thread supply position to supply the upper thread to the sewing machine. Thus, a colored upper thread in the upper thread cassette may be supplied to the sewing machine.
In the upper thread changing device, the upper thread cassette may include a cassette member that includes a cassette body formed of synthetic resin material and a cassette cover that opens or closes the cassette body, a thread wound member mounting part that mounts thereon a thread wound member winding the upper thread therearound and is provided inside the cassette member, a cutting mechanism that cuts the upper thread supplied from the thread wound member mounted on the thread wound member mounting part, and a thread end holding member that holds an end of the upper thread cut by the cutting mechanism.
The thread wound member winding the upper thread therearound may be mounted on the thread wound member mounting part provided inside the cassette member. From the upper thread cassette, an end of the upper thread may be pulled out. Then, the cassette cover may be closed. The upper thread supplied from the thread wound member may be cut by the cutting mechanism. The end of the cut upper thread may be held by the thread end holding member. Thereafter, the upper thread cassette may be mounted on the upper thread changing device to start sewing operations.
According to another aspect of the invention, there is provided an upper thread cassette that is detachably mounted on a sewing machine or an upper thread changing device for selectively supplying upper threads of a plurality of colors for sewing. The upper thread cassette may include a cassette member that includes a cassette body and a cassette cover that opens or closes the cassette body, a thread wound member mounting part that rotatably and detachably mounts thereon a thread wound member winding an upper thread therearound and is provided inside the cassette member, and a rotation controlling member that controls rotation of the thread wound member. Because the rotation controlling member may control the rotation of the thread wound member rotatably mounted on the thread wound member mounting part, the thread wound member may be prevented from rotating, for example, when the thread wound member does not have to supply the upper thread.
The upper thread cassette may further include a contacted part that makes contact with a contact part provided in the sewing machine or the upper thread changing device. The rotation controlling member may allow the thread wound member to rotate as the contacted part makes contact with the contact part when the cassette member is mounted on the sewing machine or the upper thread changing device. The rotation controlling member may prevent the thread wound member from rotating when the cassette member is not mounted on the sewing machine or the upper thread changing device.
The cassette member may include a guide section that guides an installation of the upper thread cassette onto the sewing machine or the upper thread changing device. Therefore, the upper cassette may be readily mounted onto the sewing machine or the upper thread changing device while being guided by the guide section.
According to another aspect of the invention, there is provided an upper thread cassette that is detachably mounted on a sewing machine or an upper thread changing device for selectively supplying upper threads of a plurality of colors for sewing. The upper thread cassette may include a cassette member that includes a cassette body and a cassette cover that opens or closes the cassette body, a thread wound member mounting part that mounts thereon a thread wound member winding an upper thread therearound provided inside the cassette member, an outlet that leads an end of the upper thread supplied from the thread wound member mounted on the thread wound member mounting part to the outside of the cassette member also provided in the cassette member, a cutting mechanism that cuts the upper thread supplied from the thread wound member such that a cut end of the upper thread protrudes from the outlet by a predetermined length, and a thread end holding member that holds the end of the upper thread cut by the cutting mechanism.
When the upper thread cassette is not mounted on the sewing machine or the upper thread changing device, the end of the upper thread pulled out from the thread wound member mounted on the thread wound member mounting part may be cut by the cutting mechanism, so that the cut end of the upper thread protrudes by a predetermined length from the outlet. The cut end of the upper thread is held by the thread end holding member. Then, the upper thread cassette may be mounted on the sewing machine or the upper thread changing device.
The cassette member may include a protective cover movable between a cassette mounted position where the cassette member is mounted on the sewing machine or the upper thread changing device and a cassette non-mounted position where the cassette member is not mounted on the sewing machine or the upper thread changing device. In the cassette non-mounted position, the protective cover may cover the cut end of the upper thread that protrudes. In the cassette mounted position, the protective cover may move away from the cut end of the upper thread.
Because the protective cover in the cassette non-mounted position may cover the cut end of the upper thread that protrudes by a predetermined length from the outlet, the cut end of the upper thread may not be exposed. In the cassette mounted position, the protective cover may move away from the cut end of the upper thread, so that the cut end of the upper thread may be exposed.
The cutting mechanism may include a cutter blade and a holder that holds the cutter blade. The holder may form the protective cover. In the cassette nonmounted position, the cutter blade may cut the upper thread and the holder of the cutting mechanism may cover the cut end of the upper thread that protrudes.
According to another aspect of the invention, there is provided an upper thread cassette that is detachably mounted on a sewing machine or an upper thread changing device for selectively supplying upper threads of a plurality of colors for sewing. The upper thread cassette may include a cassette member that includes a cassette body and a cassette cover that opens or closes the cassette body, a thread wound member mounting part that mounts thereon a thread wound member winding an upper thread therearound provided inside the cassette member, an outlet that leads an end of the upper thread supplied from the thread wound member to the outside of the cassette member to supply the upper thread to the sewing machine or the upper thread changing device, and a tension applying mechanism that applies tension to the upper thread supplied from the thread wound member.
In the upper thread cassette of the invention, tension may be applied by the tension applying mechanism to the upper thread to be led outside the cassette member. Therefore, the upper thread may not be excessively supplied to the sewing machine or the upper thread changing device. Thus, the occurrence of slack in the upper thread or a twisted, entangled, or overlapped upper thread is prevented.
The tension applying mechanism may be a thread holding member that is provided near the outlet and holds the upper thread led through the outlet. Therefore, while the upper thread is being held by the thread holding member near the outlet, tension may be applied to the upper thread led through the outlet.
The thread holding member may serve as a thread end holding member that holds the end of the upper thread led through the outlet. In other words, by holding the upper thread with the thread holding member, the end of the upper thread led through the outlet may be held securely.
Because the upper thread cassette may further include a tension release operation part that releases the tension applied by the tension applying mechanism by externally operating the tension applying mechanism, the tension applied to the upper thread may be released by the tension release operation part. With this structure, the upper thread may be readily let out of the upper thread cassette.